Suture anchor

ABSTRACT

An improved suture anchor is formed from body tissue. The body tissue is shaped to a desired configuration for the anchor and defines a passage through the anchor. A suture is inserted into the passage in the body tissue of the anchor. The anchor is then positioned in a patient&#39;s body with a suture extending into the passage in the anchor. The anchor may be formed of osseous body tissue, hard compact bone, dense connective body tissue, or other body tissue. The body tissue may be dried so that it absorbs fluid and expands upon being inserted into a patient&#39;s body.

BACKGROUND OF THE INVENTION

The present invention relates to a new and improved suture anchor andmore specifically to a suture anchor which is formed of body tissue.

Anchors are commonly utilized to retain sutures in a patient's body. Theanchors have previously been formed of metal, such as stainless steel ortitanium. In addition, anchors have been formed of biodegradablematerials. While being generally satisfactory, these known anchors havethe drawback that they are material which is not body tissue and areinserted into a patient's body. It has previously been suggested toconstruct anchors in the manner disclosed in U.S. Pat. Nos. 5,405,359;5,403,348; 5,203,787; 5,046,513; and 5,041,129.

SUMMARY OF THE INVENTION

The present invention relates to a new and improved suture anchor whichis formed of body tissue. The body tissue is shaped to the desiredconfiguration of the anchor. The body tissue defines a passage throughthe anchor. A suture is inserted into the passage in the anchor. Theanchor and the suture are inserted into a patient's body.

The anchor may be formed of many different types of body tissue,including osseous body tissue, bone, or dense connective tissue. Thebody tissue may be dried so that when the anchor is exposed to fluid ina patient's body, the anchor absorbs the fluid and expands. The bodytissue may be from the patient's body, from another human, or from anon-human animal.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the invention will become moreapparent upon a consideration of the following description taken inconnection with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration depicting the manner in which a thinelongated member is inserted into body tissue;

FIG. 2 is a schematic illustration, generally similar to FIG. 1,illustrating the manner in which a cutting tool is moved axially alongthe thin elongated member into the body tissue;

FIG. 3 is an enlarged schematic illustration of body tissue formed withthe thin elongated member and cutting tool of FIGS. 1 and 2;

FIG. 4 is a schematic illustration depicting the manner in which ananchor formed of the body tissue of FIG. 3 is inserted into a patient'sbody with a suture extending into the anchor;

FIG. 5 is a schematic illustration depicting the manner in which theanchor of FIG. 4, formed of body tissue, is pivoted in a patient's body;

FIG. 6 is a schematic illustration depicting the manner in which thepatient's body tissue is secured with a suture which extends into theanchor formed of body tissue;

FIG. 7 is a sectional view of an anchor formed of dense connective bodytissue;

FIG. 8 is a schematic illustration depicting the manner in which denseconnective body tissue is shaped in a press;

FIG. 9 is a schematic illustration depicting the manner in which acutting tool is used to cut an anchor from the body tissue shaped withthe press of FIG. 8; and

FIG. 10 is a schematic illustration depicting the manner in which a moldis used to shape body tissue to form an anchor.

DESCRIPTION OF SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION

General Description

Suture anchors have previously been utilized to retain sutures in eitherhard or soft tissue in a human patient's body. The suture anchors havepreviously been formed of metal, biodegradable materials, and othermaterials which do not naturally occur in a patient's body. Theinsertion of materials other than body tissue into a patient's body maybe objectionable.

In accordance with a feature of the present invention, sutures areretained in a patient's body by anchors formed of body tissue. In onespecific embodiment of the invention, the anchor is formed of bone orosseous (bonelike) tissue. In another embodiment of the invention, theanchor is formed of dense connective body tissue. The dense connectivebody tissue may contain collagen. The dense connective body tissue maybe cartilage, tendon or ligament. The dense connective body tissue maybe interarticular fibrocartilage which previously formed a meniscus in ajoint. Although it is believed that it may be preferred to use bone,osseous tissue, or dense connective tissue to form the anchor, otherbody tissue may be utilized if desired.

It is contemplated that the body tissue which is used to form the anchormay be dried. When an anchor formed of dried body tissue is insertedinto a patient's body at a location where it is exposed to the fluids inthe patient's body, the anchor absorbs the body fluid and expands. Asthe anchor expands, it presses against the surrounding tissue in thepatient's body and becomes firmly interlocked with the surroundingtissue of the patient's body.

It is contemplated that the body tissue forming the anchor may be driedin many different known ways. Specifically, the body tissue may be driedby placing it in a press and applying pressure against the body tissueto force fluid from the body tissue. Alternatively, the body tissue maybe freeze dried or dried by exposure to a relatively warm dryenvironment. The dried body tissue which forms the anchor may be bone,osseous tissue, dense connective tissue, or other body tissue. Forexample, the dried body tissue forming the anchor could be formed ofdried skin or other soft tissue and be used to retain a suture in softbody tissue.

It is contemplated that the body tissue used to form the anchor may bethe patient's own body tissue (autograft). It is believed that this hasthe advantage of minimizing the remote possibility of infecting apatient with the material of the anchor. However, the body tissueforming the anchor may be obtained from another human patient(allograft) or from a non-human animal, such as a bovine animal(xenograft).

It is contemplated that an anchor formed of body tissue in accordancewith the present invention may have many different configurations. Thus,the anchor may have a polygonal configuration or a generally sphericalconfiguration. However, it is believed that it may be preferred to formthe anchor with a cylindrical configuration and with a passage toreceive a portion of a suture.

When an anchor is to be formed, a thin elongated member may be insertedinto body tissue. The thin elongated member is used to guide a cuttingtool as it moves into the body tissue. The cutting tool forms acylindrical outer side surface of the anchor. The thin elongated memberforms a passage which extends through the anchor. Although this methodof forming the anchor may be preferred, it is contemplated that othermethods of forming the anchor could be utilized if desired. For example,the body tissue may be shaped with a press or molded to a desiredconfiguration.

Anchor Formed of Bone or Osseous Body Tissue

Body tissue 12 is illustrated schematically in FIG. 1. The body tissue12 may be disposed within a human patient's body or may be separate fromthe patient's body. The body tissue 12 may be the patient's own bodytissue or may be body tissue from another human patient. Alternatively,the body tissue 12 may be from a non-human animal, such as a bovineanimal. Although the body tissue 12 has been illustrated in FIG. 1 ashaving a polygonal configuration, the body tissue 12 may have anydesired configuration. When the body tissue 12 is disposed within apatient's body, it is contemplated that the body tissue will have aconfiguration corresponding to the configuration of a naturallyoccurring portion of the patient's body.

The body tissue 12 may be natural or artificial bone or osseous bodytissue. In the embodiment of the invention illustrated in FIG. 1, thebody tissue 12 is hard compact human bone of the type which enclosessoft cancellous bone. The bone forming the body tissue 12 may be a bonein the body of the human patient, for example, a portion of a femur of apatient. However, in FIG. 1, the body tissue 12 is illustrated as beingspaced from the patient's body.

When a suture anchor is to be formed from the body tissue 12, a thinelongated metal member 14 is inserted into the hard compact human bone.The thin elongated member 14 may be a K-wire or similar article. Thethin elongated member 14 is inserted into the hard bony body tissue 12by rotating the thin elongated member about its longitudinal centralaxis 16 and pressing a leading end of the thin elongated member againstthe body tissue.

The leading end of the thin elongated member 14 may be pointed or mayhave a flat circular configuration. If desired, the leading end of thethin elongated member 14 may be provided with a cutting edge, similar toa cutting edge used on a drill. Although it is preferred to rotate thethin elongated member 14 as it is inserted into the hard compact bone12, with other body tissue, the thin elongated member may be insertedwithout being rotated about its central axis.

In the illustrated embodiment of the thin elongated member 14, the thinelongated member has a cylindrical outer side surface with a diameterwhich corresponds to the desired diameter of a passage to be formed in asuture anchor formed of the body tissue 12. In the procedure illustratedin FIG. 1, the thin elongated member 14 is rotated about the axis 16 andpushed completely through the piece of body tissue 12. However, ifdesired, the thin elongated member 14 could be moved only part waythrough the body tissue 12. For example, when the body tissue 12 isdisposed within a patient's body, it is contemplated that the thinelongated member 14 may not be inserted completely through the portionof the patient's body formed by the body tissue.

Once the thin elongated member 14 has been inserted into the body tissue12, in the manner illustrated in FIG. 1, a rotating metal cutting tool20 is moved axially along the thin elongated member 14 into the bodytissue. The cutting tool 20 has a leading or cutting portion 22 (FIG. 2)and a trailing or guiding portion 24. The cutting portion 22 of thecutting tool 20 has a tubular cylindrical configuration. Thus, theleading or cutting portion 22 of the cutting tool 20 has a cylindricalouter side surface 28 and a cylindrical inner side surface 30. Thecutting portion 22 of the cutting tool 20 has a leading end portionwhich may form a portion of a cone or which may have cutting teeth topromote a cutting action as the cutting tool is rotated and movedaxially along the thin elongated member 14.

The trailing or guiding portion 24 of the cutting tool 20 has acylindrical outer side surface 34. The outer side surface 34 forms acontinuation of the cylindrical outer side surface 28 of the leading orcutting portion 22 of the cutting tool. In addition, the trailing orguiding portion 24 of the cutting tool 20 has a cylindrical inner sidesurface 36. The inner side surface 36 engages and is freely movablerelative to the cylindrical outer side surface of the thin elongatedmember 14.

The cylindrical inner side surface 36 of the guiding portion 24 of thecutting tool 20 engages the cylindrical outer side surface of the thinelongated member 14. This enables the guiding portion 24 to maintain theleading or cutting portion 22 of the rotating cutting tool 20 in acoaxial relationship with the thin elongated member 14. Although it ispreferred to rotate the cutting tool 20 as it is moved into the hardcompact bone 12, with other body tissue, the cutting tool may beinserted without being rotated about its central axis 16.

After the thin elongated member 14 has been inserted into the bodytissue 12, in the manner illustrated in FIG. 1, the cutting tool 20 ismoved into telescopic engagement with the thin elongated member. Thecutting tool 20 is rotated about the central axis 16 of the thinelongated member by an electric or pneumatic motor or similar device. Asthe cutting tool 20 is rotated about the longitudinal central axis 16 ofthe thin elongated member 14, the cutting tool is moved axially alongthe thin elongated member into engagement with the body tissue 12.

AS the leading or cutting portion 22 of the rotating cutting tool 20moves into engagement with the body tissue 12, the cutting portion cutsa very thin annular groove around the thin elongated member 14 in acoaxial relationship with the thin elongated member. As the cutting tool20 moves axially into the body tissue 12, a cylindrical core 40 of bodytissue is cut from the block of bone. The cylindrical core 40 of bodytissue is disposed within the tubular leading end portion 22 of thecutting tool 20. Once a core 40 of a desired axially extent has been cutin the body tissue 12, the cutting tool 20 is moved upward (as viewed inFIG. 2) along the thin elongated member and out of engagement with thebody tissue 12. The core 40 is then removed from the remaining bodytissue 12.

The core 40 (FIG. 3) has a tubular cylindrical configuration. Thecylindrical core 40 has a tubular wall 44 formed of the body tissue 12.The tubular wall 44 has a cylindrical outer side surface 46 which iscoaxial with a cylindrical inner side surface 48. The cylindrical outerside surface 46 has a diameter corresponding to the desired outsidediameter of a suture anchor. The cylindrical outer side surface 46 ofthe tubular side wall 44 was formed by and has the same diameter as theinner side surface 30 of the cutting portion 22 of the cutting tool 20.

The cylindrical inner side surface 48 of the core 40 has a diametercorresponding to the diameter of the cylindrical outer side surface ofthe thin elongated member 14. The cylindrical inner side surface 48forms a passage 50 which extends axially through the cylindrical core40. The tubular side wall 44 of the cylindrical core 40 is formed as onepiece of the body tissue 12.

The core 40 has an axial extent which is greater than the desired axialextent of a suture anchor. Therefore, the core 40 is cut, along a lineindicated at 54 in FIG. 3, to form a suture anchor 58 with a desiredaxial extent. Although the core 40 may be cut or ground to form ananchor 58 with any one of many different axially tapering or flaringconfigurations, such as those disclosed in U.S. Pat. No. 5,403,348, itis believed that it may be preferred to form the anchor 58 with acylindrical configuration.

Although it is contemplated that the tubular cylindrical suture anchor58 could be of many different sizes, it is believed that the sutureanchor may preferably have a length or axial extent of between 2 and 4millimeters. The cylindrical outer side surface 46 of the suture anchor58 may have a diameter of between 1 and 2 millimeters. The cylindricalinner side surface 48 of the passage 50 in the suture anchor 58 may havea diameter of 1/2 to 1 millimeters. Of course, the suture anchor 58could be formed with different dimensions if desired.

Since the volume of body tissue which is required to form the sutureanchor 58 is relatively small, the bone which forms the suture anchor 58can be removed from a patient's own body with minimal detrimental effectto the patient. Thus, the thin elongated member 14 may be inserted intoa bone in a patient's body. The cutting tool 20 would then be used tocut the bone in the patient's body. Of course, if desired, the bodytissue for the suture anchor 58 could be obtained from another source,such as another human or from a non-human animal.

Once the suture anchor 58 has been formed from the body tissue 12, asuture 62 (FIG. 4) is inserted into the passage 50 in the suture anchor58. The suture 62 includes a portion or leg 64 which extends away froman annular end surface 66 of the anchor 58. In addition, the suture 62has a second portion or leg 68 which extends across an annular endsurface 70 of the anchor 58. The leg 68 of the suture 62 extends alongthe cylindrical outer side surface 46 of the anchor 58 to a locationadjacent to and spaced from the leg portion 64 of the suture 62. Arelatively short portion 74 of the suture 62 interconnects the legportions 64 and 68 and is disposed in the passage 50 in the sutureanchor 58.

An inserter assembly 80 is used to position the suture anchor 58 and aportion of the suture 62 in a patient's body tissue 84. The inserterassembly 80 includes a cylindrical tubular outer sleeve 86 having acentral passage 88 in which the anchor 58 is disposed. The inserter 80also includes a tubular inner sleeve 92 which is telescopically receivedin the outer sleeve 86. The tubular inner sleeve 92 has a bevelledleading end portion 94 which engages the trailing end surface 66 of theanchor 58.

The leg or portion 64 of the suture 62 extends through a cylindricalpassage 96 in the inner sleeve 92. The leg or portion 68 of the suture62 extends through the central passage 88 in the outer sleeve 86 along apath which extends between the inner and outer sleeves. However, ifdesired, one of the legs or portions 64 or 68 of the suture could beomitted. If this was done, the suture 62 could be tied off at one end ofthe anchor 58.

It is contemplated that the anchor 58 may be inserted into a humanpatient's body at may different locations. The anchor 58 may be insertedinto either hard or soft tissue. In the situation illustratedschematically in FIG. 4, the anchor 58 is being inserted into bonetissue 84 in a patient's body. A recess 100 is formed in the bone tissue84 of the human patient's body by drilling or other methods. The recess100 extends through the hard compact outer layer 102 of the patient'sbone tissue 84 into the relatively porous inner or cancellous tissue104. The illustrated anchor 58 is formed of the same bone as the hardouter layer 102.

To insert the anchor 58 in the patient's body tissue 84, the innersleeve 92 is moved axially downward (as viewed in FIG. 4) to apply forceagainst the trailing annular end surface 66 of the anchor 58. Once theanchor 58 has been pushed into the recess 100 by axial movement of theinner sleeve 92 relative to the outer sleeve 86, the leg 68 of thesuture 62 is tensioned to apply force against the leading annular endsurface 70 of the anchor 58. At the same time, the bevelled leading end94 of the inner sleeve 92 is pressed against the trailing end surface 66of the anchor.

This results in the application of a counterclockwise (as viewed inFIGS. 4 and 5) torque to the anchor 58. This torque causes the anchor topivot through the orientation shown in FIG. 5 toward the orientationshown in FIG. 6. Once the anchor has been pivoted to the orientationshown in FIG. 6, by tensioning the suture 62 and applying force againstthe anchor with the leading end portion 94 of the inner sleeve 92, theanchor 58 engages the hard compact outer layer 102 of the patient's bonetissue 84 to hold the anchor in the recess 100.

The suture 68 can then be used to secure body tissue 110 in place. Thebody tissue 110 may be soft tissue, or a 20 ligament, or a tendon, orother body tissue. If desired, the suture 62 may be used to secure animplant or splint in place relative to the patient's body tissue 84.

One specific known inserter assembly 80 and method of inserting a sutureanchor 58 into a patient's body tissue has been illustrated in FIGS.4-6. This specific inserter assembly and the method of inserting theanchor 58 are the same as is disclosed in U.S. Pat. No. 5,403,348 issued

Apr. 4, 1995 and entitled "Suture Anchor". However, it is contemplatedthat many different known types of inserter assemblies could be utilizedto install the suture anchor with many different methods in a patient'sbody tissue. For example, the inserter assembly and method disclosed inU.S. Pat. No. 5,464,426 issued Nov. 7, 1995 and entitled "Method ofClosing Discontinuity in Tissue" could be utilized if desired. Ofcourse, other known apparatus and methods could also be utilized ifdesired.

In the embodiment of the invention illustrated in FIGS. 1-6, the anchor58 is formed of hard compact outer bone. However, it is contemplatedthat the anchor 58 could be formed of osseous body tissue other thanhard compact bone. The osseous body tissue could be obtained from thepatient or from other sources.

Anchor Formed of Dense Connective Body Tissue

In the embodiment of the invention illustrated in FIGS. 1-6, the anchor58 is formed of osseous tissue. In the embodiment of the inventionillustrated in FIGS. 7-9, an anchor is formed of dense connective bodytissue. Since the embodiment of the invention illustrated in FIGS. 7-9is generally similar to the embodiment of the invention illustrated inFIGS. 1-6, similar numerals will be utilized to identify similarcomponents, the suffix letter "a" being associated with the componentsof FIGS. 7-9 to avoid confusion.

A suture anchor 58a formed of dense connective body tissue isillustrated in FIG. 7. The suture anchor 58a has the same configurationas the suture anchor 58 of FIGS. 3 and 4. The suture anchor 58acooperates with a suture in the same manner as in which the sutureanchor 58 cooperates with the suture 62 (FIGS. 4-6).

The suture anchor 58a (FIG. 7) has a cylindrical tubular side wall 44aformed of dense connective body tissue. The tubular side wall 44a has acylindrical outer side surface 46a and a cylindrical inner side surface48a which extend between axially opposite annular end surfaces 66a and70a of the suture anchor 58a. The cylindrical inner side surface 48a isdisposed in a coaxial relationship with the cylindrical outer sidesurface 46a and defines a passage 50a which extends axially through thesuture anchor 58a.

Although the suture anchor 58a has a tubular cylindrical configuration,it is contemplated that the suture anchor 58a could have a differentconfiguration if desired. For example, the suture anchor 58a could havea polygonal configuration. If desired, the suture anchor 58a could beformed with a spherical configuration. The suture anchor 58a may have anaxially tapering or flaring configuration, similar to the configurationsof anchors disclosed in the aforementioned U.S. Pat. No. 5,403,348.

In accordance with a feature of this embodiment of the invention, thesuture anchor 58a is formed of dense connective body tissue 120. Thedense connective body tissue contains collagen. It is contemplated thatthe dense connective body tissue 120 may be formed from ligaments ortendon. It is also contemplated that the dense connective body tissue120 may be formed from cartilage, such as interarticular fibrocartilagewhich forms a meniscus in a joint. It should be understood that denseconnective body tissue other than the specific examples set forth abovemay be utilized if desired. The dense connective body tissue 120 formingthe suture anchor 58a may be removed from a patient's own body.Alternatively, the dense connective body tissue may be obtained from ahuman other than the patient into which the suture anchor 58a is to beinserted. If desired, the dense connective body tissue 120 could beobtained from a non-human animal, such as a bovine animal. However, itis believed that it may be preferred to use a patient's own denseconnective body tissue to form the suture anchor 58a in order tominimize any possibility of infection. If the dense connective bodytissue is obtained from a source other than a patient's own body, it maybe desired to sterilize the dense connective body tissue using ethyleneoxide gas or other sterilizing agents.

Although the dense connective body tissue 120 could be shaped in manydifferent ways, it is preferred to place the dense connective bodytissue in a press 122 (FIG. 8). The press 122 has an upper platen 124which presses the dense connective body tissue 120 against a lowerplaten 126 to form a flat sheet 130 of dense connective body tissue. Theflat sheet 130 has a thickness, as measured perpendicular to parallelflat upper and lower major side surfaces 134 and 136 (FIG. 9) of theflat sheet, which is equal to the desired axial extent of the sutureanchor 58a (FIG. 7). Thus, the thickness of the flat sheet 130 is equalto the distance between opposite annular end surfaces 66a and 70a (FIG.7) of the suture anchor 58a.

A cutting tool 20a (FIG. 9) is used to cut the sheet 130 to form thesuture anchor 58a. The cutting tool 130 includes a thin elongated member14a having a cylindrical outer side surface with a diameter whichcorresponds to the diameter of the passage 50a in the suture anchor 58a(FIG. 7). In the illustrated embodiment of the cutting tool 20a, aleading end portion 142 of the thin elongated member 14a has a sharpconical configuration. However, if desired, the leading end portion 142could have a flat circular configuration. Alternatively, the leading endportion 142 of the thin elongated member 14a could have a thin hollowtubular configuration.

The cutting tool 20a has a leading or cutting portion 22a. The leadingor cutting portion 22a has a cylindrical outer side surface 28a and acylindrical inner side surface 30a. The cutting portion 22a of thecutting tool 20a has a sharp leading end portion 144 which is formed asa portion of a right circular cone having a central axis which iscoincident with the central axis of the cutting tool 20a and with thecentral axis of the thin elongated member 14a. A trailing portion 24a ofthe cutting tool 20a is gripped by a drive device (not shown).

When the suture anchor 58a is to be formed from the sheet 130 of denseconnective body tissue 120, the drive device moves the cutting tool 20astraight downward (as viewed in FIG. 9) without rotating the cuttingtool. As the cutting tool 20a moves downward, the thin elongated member14a is inserted into and pierces the sheet 130 of dense connective bodytissue 120. Immediately after the leading end portion 142 of the thinelongated member 14a enters the sheet 130 of dense connective bodytissue 120, the leading end portion 144 of the cutting portion 22aengages the sheet 130 of dense connective body tissue. Continueddownward (as viewed in FIG. 9) movement of the cutting tool 20a resultsin the cutting portion 22a of the cutting tool cutting the sheet 130 ofdense connective body tissue with a cookie cutter type action.

This results in a cylindrical opening being formed in the sheet 130 andin a body of dense connective body tissue 120 being disposed in thecutting tool 20a. The body of dense connective body tissue is removedfrom the cutting tool 20a with a suitable ejector (not shown). The bodyof dense connective body tissue 120 which is ejected from the cuttingtool 20a will have a configuration corresponding to the configuration ofthe suture anchor 58a. It should be noted that the cutting tool 20a isreciprocated with a linear cutting and return stroke and is not rotatedabout its central axis as is the cutting tool 20 of FIG. 2.

If desired, the cutting tool 20a and thin elongated member 14a could berotated together about their common central axis as they are moved intothe body tissue 120. This would result in the same type of cuttingaction as is obtained with the separate thin elongated member 14 andcutting tool 20 of FIGS. 1 and 2. However, the rotating thin elongatedmember 14a and cutting tool 20a would cut the body tissue simultaneouslyrather than sequentially as in FIGS. 1 and 2.

It should be understood that a separate thin elongated member,corresponding to the thin elongated member 14 of FIGS. 1 and 2, and arotatable cutting tool, corresponding to the cutting tool 20 could beutilized to cut the dense connective body tissue. If desired, the denseconnective body tissue could have a configuration other than theconfiguration of the sheet 130. Thus, a relatively large block or pieceof dense connective body tissue could be provided. Alternatively, thedense connective body tissue of the anchor 58a could be obtaineddirectly from the patient's own body with the cutting tool 20a.

For example, the thin elongated member 14 could be inserted axially intothe dense connective body tissue in the manner illustrated in FIG. 1 forthe body tissue 12. The thin elongated member could be inserted into thedense connective body tissue while the thin elongated member is beingrotated and pressed against the dense connective body tissue in the samemanner as described in conjunction with the body tissue 12 of FIG. 1.The rotating cutting tool 20 will then cut a relatively long cylindricalcore of dense connective body tissue. Once the core of dense connectivebody tissue has been removed from the cutting tool 20 and the thinelongated member 14, the cylindrical core of dense connective bodytissue would be cut to a length corresponding to the desired length ofthe suture anchor 58a.

It is also contemplated that a suitable press could be utilized to shapethe dense connective body tissue into the cylindrical configuration ofthe anchor 58a. Thus, a press having a construction similar to theconstruction disclosed in U.S. Pat. No. 5,329,846 issued Jul. 19, 1994and entitled "Tissue Press and System" could be utilized to form thedense connective body tissue to a cylindrical configuration. If desired,the body tissue could be shaped around a thin elongated member which issubsequently withdrawn to form the passage 50a. Alternatively, the thinelongated member could be inserted into a cylindrical piece of denseconnective body tissue to form the passage 50a after the body tissue hasbeen removed from the press or while the body tissue is still in thepress.

Once the suture anchor 58a has been formed, a suture is inserted intothe passage 50a and the suture anchor is inserted into the body of apatient. The suture anchor 58a may be inserted to the body of a patientusing an inserter assembly having the same construction as the inserterassembly 80 of FIGS. 4 and 5. Once the suture anchor 58a has been pushedinto a patient's body, the suture is tensioned and force is appliedagainst the trailing end of the suture anchor by the inner sleeve of theinserter to pivot the suture anchor in the manner illustratedschematically in FIG. 5. Of course, the suture anchor 58a may beinserted into either hard or soft body tissue in a manner which isdifferent than the manner illustrated schematically in FIGS. 4 and 5using an inserter assembly having a different construction than theinserter assembly 80.

Molded Suture Anchor

In the embodiments of the invention illustrated in FIGS. 1-9, the sutureanchors 58 and 58a were formed by cutting and/or pressing body tissue.In the embodiment of the invention illustrated in FIG. 10, the sutureanchor is formed by molding body tissue. Since the embodiment of theinvention illustrated in FIG. 10 is generally similar to the embodimentsof the invention illustrated in FIGS. 1-9, similar numerals will beutilized to designate similar components, the suffix letter "b" beingassociated with the numerals of FIG. 10 to avoid confusion.

When a suture anchor 58b is to be formed, particles of body tissue, suchas natural or artificial osseous body tissue, is positioned in a mold150. The mold 150 includes upper and lower mold sections 152 and 154which cooperate to define a cylindrical mold chamber 156. Thecylindrical mold chamber 156 has a length corresponding to the desiredaxial extent of the suture anchor 58b. The mold chamber 156 has adiameter which corresponds to the desired diameter of the cylindricalouter side surface of the suture anchor 58b.

A cylindrical thin elongated member or core 160 extends axially throughthe mold chamber 156. An end plate 164 closes one end of the moldchamber 156 and supports one end of the core 160. A second end plate(not shown) closes the opposite end of the mold chamber 156 and supportsthe opposite end of the core 160.

Particles of bone and a suitable binder are conducted into the moldchamber. It is believed that it may be preferred to use fibrin as thebinder. The natural or artificial bone particles are uniformly coatedwith the fibrin and completely fill the mold chamber 156. The fibrin issolidified around and interconnects the particles of body tissue to formthe suture anchor 58b. It is contemplated that pressure may be appliedagainst the mixture of binder and particles of body tissue in the mold150 to compact the mixture.

Suture Anchor Formed of Dried Body Tissue

Regardless of which of the various body tissues and methods are utilizedto form a suture anchor, it is contemplated that the body tissue may bedried. When a suture anchor formed of dried natural or artificial bodytissue is inserted into a patient's body, the suture anchor is exposedto the fluid in the patient's body. The dried tissue of the sutureanchor will absorb the fluid in the patient's body.

As the dried suture anchor absorbs the fluids in the patient's body, thesuture anchor expands. As the suture anchor expands, it presses againstthe surrounding tissue of the patient's body and interlocks the sutureanchor and the patient's body.

The suture anchor of dried body tissue can be inserted into an openingin a patient's body in the manner illustrated schematically for thesuture anchor 58 in FIGS. 4 and 5. The suture anchor of dried bodytissue is inserted into the recess 100 and is pivoted in the same manneras previously explained in conjunction with the embodiment of theinvention illustrated in FIGS. 4 and 5. Once a suture anchor has beenpivoted relative to the patient's body from the orientation shown inFIG. 4 through the orientation shown in FIG. 5 to the orientation shownin FIG. 6, the suture anchor absorbs body fluids and expands to morecompletely fill the recess 100.

It is contemplated that the suture anchor may be formed of manydifferent types of dried body tissue. Thus, the suture anchor may beformed of dried osseous or bony body tissue. Alternatively, the sutureanchor may be formed of dried dense connective body tissue, such ascartilage or tendon tissue. Although hard compact bone tissue may bedried, there will be relatively little expansion of the hard compactbone tissue when it is inserted into the patient's body.

When a suture anchor is formed of dried body tissue, the expansion orswelling of the suture anchor can be used to retain the suture anchor ata location where it would not be retained without expanding or swelling.Thus, a suture anchor formed of dried skin or other soft tissue may beinserted beneath the skin of the patient. The dried skin or other softtissue forming the suture anchor will immediately begin to absorb thepatient's body fluid (blood). As this occurs, the suture anchor willexpand. Expansion of the suture anchor beneath the skin of the patientwill prevent the suture anchor from being pulled back through theopening through which it was inserted beneath the skin of the patient.

Anchors formed of dried soft body tissue may be used at many differentlocations in a patient's body. For example, suture anchors formed ofdried soft body tissue may be used in association with internal organs.The dried soft body tissue forming a suture anchor may be obtained fromany one of many different sources. For example, body tissue may beobtained from inside a human other than the patient or from inside anon-human animal. This body tissue would be sterilized and dried beforebeing formed into a suture anchor.

It is contemplated that the body tissue from which a suture anchor is tobe formed may be dried in many different ways. Thus, the body tissue maybe freeze dried. When a suture anchor is to be formed, a thin elongatedmember, corresponding to the thin elongated member 14 of FIG. 1, isinserted into the freeze dried body tissue. The cutting tool 20 is thenrotated and moved axially along the thin elongated member to cut thefreeze dried body tissue in the same manner illustrated schematically inFIG. 2.

Rather than freeze drying the body tissue, the body tissue could bedried by applying pressure against the body tissue and forcing fluid toflow from the body tissue. Thus, a press, similar to a press disclosedin U.S. Pat. No. 5,329,846 issued Jul. 19, 1994 and entitled "TissuePress and System" may be utilized to apply pressure against body tissueand force fluid from the body tissue. When the body tissue is dried inthis manner, the body tissue may be compressed to a cylindricalconfiguration with an outside diameter which corresponds to the outsidediameter of a suture anchor.

A passage may be formed in the compressed and dried body tissue eitherbefore or after it is removed from the press. When the body tissue hasbeen removed from the press, it can be further dried by being exposed toa warm dry environment. Alternatively, the body tissue may be driedwithout pressing, by exposing the body tissue to a warm dry environmentfor a sufficient length of time to result in evaporation of the fluidfrom the body tissue.

Conclusion

The present invention relates to a new and improved suture anchor 58which is formed of body tissue. The body tissue is shaped to the desiredconfiguration of the anchor 58. The body tissue defines a passage 50through the anchor 58. A suture 62 is inserted into the passage 50 inthe anchor 58. The anchor 58 and the suture 62 are inserted into apatient's body.

The anchor 58 may be formed of many different types of body tissue,including osseous body tissue, bone or dense connective tissue. The bodytissue may be dried so that when the anchor 58 is exposed to fluid in apatient's body, the anchor absorbs the fluid and expands. The bodytissue may be from the patient's own body, from another human, or from anonhuman animal.

Having described the invention, the following is claimed:
 1. A method ofanchoring a suture, said method comprising the steps of forming ananchor of body tissue, said step of forming an anchor of body tissueincludes forming an outer side surface of the anchor defined by bodytissue while a thin member extends into the body tissue and, thereafter,removing the thin member from the body tissue to form a passage in theanchor, inserting a suture into the passage, and positioning the anchorformed of body tissue in a patient's body with the suture extending intothe passage formed in the anchor.
 2. A method as set forth in claim 1wherein said step of forming an anchor of body tissue includes formingthe anchor of osseous body tissue.
 3. A method as set forth in claim 1wherein said step of forming an anchor of body tissue includes formingan anchor of dried body tissue, said step of positioning the anchorformed of body tissue in a patient's body includes positioning theanchor at a location in the patient's body where the dried body tissueof the anchor is exposed to body fluid to enable the dried body tissueof the anchor to absorb body fluid.
 4. A method as set forth in claim 1wherein said step of forming an anchor of body tissue includes formingthe anchor of body tissue which includes collagen.
 5. A method as setforth in claim 1 wherein said step of forming an anchor of body tissueincludes forming the anchor of interarticular fibrocartilage.
 6. Amethod as set forth in claim 1 wherein said step of forming an anchor ofbody tissue includes forming the anchor from body tissue removed fromthe body of the patient, said step of positioning the anchor formed ofbody tissue in the patient's body includes positioning the anchor in thebody of the patient from whom the body tissue forming the anchor wasremoved.
 7. A method as set forth in claim 1 wherein said step offorming an anchor of body tissue includes forming the anchor from bodytissue removed from a first human, said step of positioning the anchorformed of body tissue in a patient's body includes positioning theanchor in the body of a second human.
 8. A method as set forth in claim1 wherein said step of forming an anchor of body tissue includes formingthe anchor from body tissue removed from an animal other than a human,said step of positioning the anchor formed of body tissue in a patient'sbody includes positioning the anchor in the body of a human.
 9. A methodas set forth in claim 1 wherein said step of positioning the anchorformed of body tissue in a patient's body with the suture extending intothe passage includes moving the anchor formed of body tissue into thepatient's body, and, thereafter pivoting the anchor relative to thepatient's body.
 10. A method as set forth in claim 9 wherein said stepof pivoting the anchor includes tensioning the suture to apply force tothe anchor.
 11. A method as set forth in claim 11 wherein said step offorming an anchor of body tissue further includes moving the thin memberinto the body tissue, said step of forming an outer side surface of theanchor defined by body tissue includes moving a cutting tool along thethin member and cutting the body tissue with the cutting tool whilemoving the cutting tool along the thin member.
 12. A method as set forthin claim 11 wherein said step of removing the thin member from the bodytissue is performed after moving the cutting tool along the thin memberand cutting the body tissue with the cutting tool.
 13. A method as setforth in claim 1 wherein said step of forming an outer side surface ofthe anchor defined by body tissue includes compacting body tissue aroundthe thin member.
 14. A method as set forth in claim 1 wherein said stepof forming an outer side surface of the anchor defined by body tissueincludes forming a side surface of the anchor by cutting body tissuewith a first cutting tool while the thin member extends into the bodytissue, said step of forming an anchor of body tissue further includescutting the body tissue with a second cutting tool to form an endsurface of the anchor after having performed said step of removing thethin member from the body tissue.
 15. A method as set forth in claim 1wherein said step of forming an outer side surface of the anchor definedby body tissue includes forming a side surface of the anchor by cuttingbody tissue with a cutting tool, said method further including movingthe thin member relative to the body tissue with the cutting tool whilecutting body tissue with the cutting tool.
 16. A method as set forth inclaim 15 wherein said steps of cutting body tissue with a cutting tooland moving the thin member relative to the body tissue with the cuttingtool includes simultaneously rotating the thin member and the cuttingtool about a common axis.
 17. A method as set forth in claim 15 whereinsaid steps of cutting body tissue with a cutting tool and moving thethin member relative to body tissue are performed with the thin memberfixedly connected with the cutting tool to maintain a constant spatialrelationship between the cutting tool and the thin member.
 18. A methodas set forth in claim 1 wherein said step of forming an outer sidesurface of the anchor defined by body tissue includes forming acylindrical outer side surface having a central axis which is coincidentwith a central axis of the thin member.
 19. A method as set forth inclaim 1 wherein said step of forming an outer side surface of the anchordefined by body tissue includes applying pressure against the bodytissue to shape the body tissue to a desired configuration.
 20. A methodas set forth in claim 1 wherein said step of forming an anchor of bodytissue includes positioning the body tissue in a press and operating thepress to apply pressure against the body tissue to shape the body tissueto a desired configuration.
 21. A method as set forth in claim 1 whereinsaid step of forming an anchor of body tissue includes forming a sheetof body tissue, said step of forming an outer side surface of the anchordefined by body tissue includes cutting the sheet of body tissue with acutting tool.
 22. A method as set forth in claim 1 wherein said step offorming an anchor of body tissue further includes forming a piece ofdried body tissue, said step of forming an outer side surface of theanchor defined by body tissue includes cutting the piece of dried bodytissue.
 23. A method as set forth in claim 22 wherein said step offorming a piece of dried body tissue includes compressing the bodytissue to remove fluid from the body tissue.
 24. A method as set forthin claim 1 further including the step of expanding the anchor under theinfluence of fluid absorbed from the patient's body after havingperformed said step of positioning the anchor formed of body tissue inthe patient's body.
 25. A method of anchoring a suture, said methodcomprising the steps of inserting a thin elongated member into osseoustissue, moving a cutting tool axially along the thin elongated memberinto engagement with the osseous tissue at a location spaced from thethin elongated member and extending around a portion of the thinelongated member, moving the cutting tool into the osseous tissue bycutting the osseous tissue with the cutting tool while continuing tomove the cutting tool axially along the thin elongated member, said stepof moving the cutting tool into the osseous tissue includes guidingmovement of the cutting tool into the osseous tissue with the thinelongated member, separating a portion of the osseous tissue having anouter side surface formed by the cutting tool from the remainder of theosseous tissue, removing the thin elongated member from the osseoustissue to leave a passage at the location where the thin elongatedmember was inserted into the osseous tissue, inserting a suture into thepassage in the osseous tissue, and inserting at least part of theportion of the osseous tissue having an outer side surface formed by thecutting tool and a portion of the suture into a patient's body with thesuture extending into the passage in the osseous tissue.
 26. A method asset forth in claim 25 further including the steps of tensioning thesuture to transmit force from the suture to the osseous tissue having anouter side formed by the cutting tool, and transmitting force from theosseous tissue having an outer side formed by the cutting tool to thepatient's body to retain a portion of the suture in the patient's body.27. A method as set forth in claim 25 wherein said step of inserting athin elongated member into osseous tissue includes inserting the thinelongated member into osseous tissue in the patient's body, said step ofmoving a cutting tool axially along the thin elongated member intoengagement with the osseous tissue includes moving the cutting tool intoengagement with osseous tissue in the patient's body, said step ofseparating a portion of the osseous tissue from the remainder of theosseous tissue includes removing the osseous tissue from the patient'sbody.
 28. A method as set forth in claim 25 wherein said step ofinserting a thin elongated member into osseous tissue includes insertingthe thin elongated member into osseous tissue which is spaced from thepatient's body, said step of moving a cutting tool axially along thethin elongated member into engagement with the osseous tissue includesmoving the cutting tool into engagement with the osseous tissue which isspaced from the patient's body.
 29. A method as set forth in claim 25wherein said step of inserting a thin elongated member into osseoustissue includes rotating the thin elongated member about a longitudinalaxis of the thin elongated member while pressing an end of the thinelongated member against the osseous tissue.
 30. A method as set forthin claim 25 wherein said step of cutting the osseous tissue with thecutting tool includes rotating the cutting tool about a longitudinalaxis of the thin elongated member.
 31. A method as set forth in claim 25further including cutting the portion of the osseous tissue separatedfrom the remainder of the osseous tissue into a plurality of segmentseach of which has an outer side surface formed by the cutting tool, saidstep of inserting a suture into the passage in the osseous tissueincludes inserting a suture through one of the segments of osseoustissue.
 32. A method as set forth in claim 25 wherein said step ofinserting a suture into the passage in the osseous tissue includesinserting the suture through the passage so that a first portion of thesuture extends to a first end of the passage in the osseous tissue and asecond portion of the suture extends from a second end of the passage inthe osseous tissue, said step of inserting the portion of the osseoustissue having an outer side surface formed by the cutting tool and aportion of the suture into a patient's body is performed with the firstand second portions of the suture extending from one side of a locationwhere the portion of the osseous tissue is inserted into the patient'sbody to the first and second ends of the passage in the osseous tissue.33. A method of anchoring a suture, said method comprising the steps offorming a piece of bone to have first and second circular ends, acylindrical an outer side surface extending between said first andsecond ends, and a passage extending through the piece of bone from thefirst end to the second end, inserting a suture into the passage in thepiece of bone, and inserting the piece of bone into body tissue with thefirst circular end of the piece of bone leading, with the secondcircular end of the piece of bone trailing, and with the sutureextending from the passage in the piece of bone, said step of insertingthe piece of bone into the body tissue includes applying force againstthe trailing second circular end of the piece of bone with an insertermember.
 34. A method as set forth in claim 33 wherein said step offorming a piece of bone includes inserting a thin elongated member intoa body of bone moving a cutting tool axially along the thin elongatedmember into the body of bone and cutting the body of bone with thecutting tool to form the outer side surface of the piece of bone as thecutting tool is moved into the body of. bone.
 35. A method as set forthin claim 34 wherein said step of forming a piece of bone includesdisengaging the thin elongated member from the bone to leave a passagein the bone.
 36. A method as set forth in claim 34 wherein the body ofbone is spaced from a patient, said step of inserting the piece of boneinto body tissue includes inserting the piece of bone into the patient'sbody.
 37. A method as set forth in claim 34 wherein the body of bone isdisposed in a patient's body, said step of inserting a thin elongatedmember into a body of bone includes inserting the thin elongated memberinto the patient's body, said step of forming a piece of bone includesremoving bone from the patient's body, said step of inserting the pieceof bone into body tissue includes inserting the piece of bone into thepatient's body.
 38. A method as set forth in claim 33 wherein said stepof forming a piece of bone includes compressing a mixture of boneparticles and a binder.
 39. A method as set forth in claim 33 whereinsaid step of forming a piece of bone includes rotating a cutting tooland moving the cutting tool into bone along a path which extendsparallel to an axis about which the cutting tool is rotated to at leastpartially form the outer side surface of the piece of bone.
 40. A methodas set forth in claim 39 wherein said step of forming a piece of boneincludes rotating a thin elongated member and moving the thin elongatedmember into bone along a path which extends parallel to an axis aboutwhich the thin elongated member is rotated to at least partially formthe passage which extends through the piece of bone.
 41. A method as setforth in claim 40 wherein said steps of rotating a cutting tool andmoving the cutting tool into bone and said steps of rotating a thinelongated member and moving the thin elongated member into bone areperformed together.
 42. A method as set forth in claim 40 wherein saidsteps of rotating a cutting tool and moving the cutting tool into boneare performed after performance of said step of rotating a thinelongated member and moving the thin elongated member into bone.
 43. Amethod as set forth in claim 33 wherein said step of forming a piece ofbone includes forming a piece of bone which is at least partially dried,said step of inserting the piece of bone into body tissue includespositioning the piece of bone in body tissue at a location where thepiece of bone is exposed to body fluid to enable the piece of bone toabsorb body fluid.
 44. A method of anchoring a suture, said methodcomprising the steps of forming a cylindrical anchor of hard compactbone, said step of forming a cylindrical anchor of hard compact boneincludes forming a core having a cylindrical outer side surface formedof hard compact bone and a passage extending through the core, said corehaving an axial extent which is greater than a desired length of theanchor, and cutting from the core a cylindrical piece of hard compactbone which has an axial extent corresponding to the desired length ofthe anchor and through which the passage axially extends, said methodfurther including the steps of inserting a suture into the passage inthe cylindrical piece of hard compact bone which forms the anchor, andpositioning the cylindrical piece of hard compact bone which forms theanchor in a patient's body with the suture extending into the passageformed in the cylindrical piece of hard compact bone.
 45. A method asset forth in claim 44 wherein said step of forming a core having acylindrical outer side surface formed of hard compact bone and a passageextending through the core includes moving a thin member into the hardcompact bone to form the passage and cutting the hard compact bone witha cutting tool while the thin member is disposed in the hard compactbone.
 46. A method as set forth in claim 44 wherein said step of forminga core having a cylindrical outer side surface formed of hard compactbone and a passage extending through the core includes moving a thinmember into the hard compact bone to form the passage and moving acutting tool along the thin member to form the cylindrical outer sidesurface of the core with a longitudinal central axis of the cylindricalouter side surface of the core coincident with a central axis of thepassage.
 47. A method of anchoring a suture, said method comprising thesteps of inserting a thin elongated member into hard compact bone,moving a rotating cutting tool into the hard compact bone by cutting thehard compact bone with the rotating cutting tool while the thinelongated member extends into the hard compact bone, removing the thinelongated member from the hard compact bone to leave a passage at thelocation where the thin elongated member was inserted into the hardcompact bone, inserting a suture into the passage in the hard compactbone, and inserting the hard compact bone having an outer side surfaceformed by the cutting tool and a portion of the suture into a patient'sbody with the suture extending into the passage in the hard compactbone.
 48. A method as set forth in claim 47 further including the stepsof tensioning the suture to transmit force from the suture to the hardcompact bone having an outer side formed by the cutting tool, andtransmitting force from the hard compact bone having an outer sideformed by the rotating cutting tool to the patient's body to retain aportion of the suture in the patient's body.
 49. A method as set forthin claim 47 wherein said step of inserting a thin elongated member intohard compact bone includes inserting the thin elongated member into hardcompact bone in the patient's body, said step of moving a rotatingcutting tool into engagement with the hard compact bone includes movingthe rotating cutting tool axially along the thin elongated member intoengagement with hard compact bone in the patient's body.
 50. A method asset forth in claim 47 wherein said step of inserting a thin elongatedmember into hard compact bone includes simultaneously rotating the thinelongated member and cutting tool about a longitudinal axis of the thinelongated member while pressing an end of the thin elongated memberagainst the hard compact bone.
 51. A method of anchoring a suture, saidmethod comprising the steps of forming an anchor of body tissue, saidstep of forming an anchor of body tissue includes rotating a thinelongated member and a cutting tool together about a longitudinal axisof the thin elongated member, simultaneously moving the rotating cuttingtool and rotating thin elongated member into the body tissue, forming acylindrical outer side surface of a core of body tissue with therotating cutting tool as the rotating cutting tool is moved into thebody tissue, forming a passage extending axially through the core ofbody tissue with the rotating thin elongated member as the rotating thinelongated member is moved into the body tissue, removing the core ofbody tissue from body tissue from which the core was cut by the rotatingcutting tool, said core of body tissue having an axial extent which isgreater than a desired length of the anchor, removing the thin elongatedmember from the core of body tissue to form a passage extending throughthe core of body tissue, and cutting from the core of body tissue acylindrical piece of body tissue having an axial extent corresponding tothe desired length of the anchor and through which the passage extends,said method further including the steps of inserting a suture into thepassage formed in the cylindrical piece of body tissue which forms theanchor, and positioning the cylindrical piece of body tissue which formsthe anchor in a patient's body with the suture extending into thepassage formed in the cylindrical piece of body tissue, said step ofpositioning the cylindrical piece of body tissue which forms the anchorin a patient's body includes applying force against a trailing end ofthe anchor with a tubular inserter member having a passage through whicha first portion of the suture extends and pivoting the anchor relativeto the tubular inserter member by tensioning a second portion of thesuture to apply force to a leading end of the anchor.
 52. A method asset forth in claim 51 further including the step of drying the bodytissue prior to performance of said step of forming an anchor of bodytissue, said step of positioning the cylindrical piece of body tissuewhich forms the anchor in a patient's body includes positioning theanchor at a location in the patient's body where the anchor is exposedto the patient's body fluid to enable the anchor to absorb the patient'sbody fluid and expand in the patient's body.